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# Re: st: Spline after Cox regression

 From Etan Lakam To statalist@hsphsun2.harvard.edu Subject Re: st: Spline after Cox regression Date Tue, 9 Jul 2013 17:24:35 -0400

```Thanks, will try it and let you know.
Etan

On Tue, Jul 9, 2013 at 1:24 PM, Nick Cox <njcoxstata@gmail.com> wrote:
> I was explaining the error message, not commenting on your strategy.
> Perhaps you should look at -margins- and -marginsplot-.
> Nick
> njcoxstata@gmail.com
>
>
> On 9 July 2013 15:27, Etan Lakam <etan.lakam@googlemail.com> wrote:
>> How do I circumvent this problem then?
>> Etan
>>
>> On Sun, Jul 7, 2013 at 2:19 AM, Nick Cox <njcoxstata@gmail.com> wrote:
>>> So, -adjust- is evidently objecting to being asked to do something 1064 times.
>>>
>>> Nick
>>> njcoxstata@gmail.com
>>>
>>> Etan Lakam
>>>
>>>> Yes lnffa is the variable I intended to use, it  has 1064 distinct values.
>>>
>>> Nick Cox
>>>
>>>>>> How many distinct values does -lnffa- have? Was that the variable you
>>>>>> meant to use?
>>>
>>> Etan Lakam
>>>
>>>>>> > I am doing Cox-regression with a continuous exposure ffa and the
>>>>>> > outcome hf, I have been trying to model it as  cubic spline.
>>>>>> > Here is how I approached it, adjusting for age, sex, and race, however
>>>>>> > it is coming up with the message error below, and I cannot obtain the
>>>>>> > graph
>>>>>> > I do not have a clue about what is happening.
>>>
>>>>>> > mkspline  rlnffa= lffa, cubic nknots(5)
>>>>>> > stcox rlnratio* sex race age
>>>>>> > adjust race=0 sex=1 age, by(lnffa) ci replace exp
>>>>>> >
>>>>>> > ------------------------------------------------------------------------------------------
>>>>>> >      Dependent variable: _t     Command: stcox
>>>>>> >    Variables left as is: rlnffa1, rlnffa2
>>>>>> >   Covariate set to mean: age = 53.900191
>>>>>> > Covariates set to value: race = 0, sex = 1
>>>>>> >
>>>>>> > ------------------------------------------------------------------------------------------
>>>>>> > too many values
>>>>>> > r(134);
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```